battery charger making high pitched whine....?

Its a cheap 2 bay trustfire -- I've already ordered a nitecore and am planning on using the trustfire as a backup. But I loaded my 18650 in it and it's making a very audible whine. Is this reason to be concerned (or downright terrified?) or just normal?

I have the same charger and it has done that ever since I got it almost 2 years ago. I was actually going to mention it on here, so great question. I've never had a problem. Mine seems worse when you first put a battery in it and then the noise slowly tapers off as it charges longer.

on the subject of charging, I don't have any metering equipment ... am I in the danger zone as far as not knowing whether I've overdrained the battery prior to charging? I'm using Ego T 18650 and anyvape 18350 battery tubes with Ego T and Evic Easy heads.

Coil whine is not due to poor quality capacitors. You only need ask the people who own some of the Seasonic X-Series power supplies that use all Japanese 105°C electrolytic capacitors and are afflicted with this problem.

Coil whine may also happen on the coils/chokes in VRM circuits of motherboards and graphics cards.

The coil/choke is a coil of wire wrapped around a ferrite core. If the core is loose it will vibrate at some harmonic of the PSU's switching frequency.

If the warranty on the device has already expired, I have heard of some people solving this problem by applying nail polish or hot-melt glue to the offending coil(s) to prevent the core from vibrating.

Coil whine is considered a manufacturing defect. Sometimes it's caused during shipping of the PSU to the end user. You really don't know if the package has been thrown around during its transport.

Computer people and anyone working with electronics and coils wrapped on ferrite beads for transformers know this sound all to well...

It shouldn't be a problem...other than being annoying as heck!

It is fixable...but ONLY by someone who knows about electronics and knows what they are doing!!! (aka putting a dab of clear nail polish in the coil which soaks in, dries and binds the coil so it doesn't vibrate)

on the subject of charging, I don't have any metering equipment ... am I in the danger zone as far as not knowing whether I've overdrained the battery prior to charging? I'm using Ego T 18650 and anyvape 18350 battery tubes with Ego T and Evic Easy heads.

The Ego-T 2 heads have the same low battery protection circuitry as any Joyetech 510 or eGo battery: it shuts the device off when the battery voltage has dropped to 3.2 volts.